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  • 1
    Electronic Resource
    Electronic Resource
    Trophic interactions in soils as they affect energy and nutrient dynamics. III. Biotic interactions of bacteria, amoebae, and nematodes (1977)
    Springer
    Microbial ecology 4 (1977), S. 361-371 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Bacteria (Pseudomonas), amoebae (Acanthamoeba), and nematodes (Mesodiplogaster) were raised in soil microcosms with and without glucose additions. Nematode and amoebal grazing on bacteria significantly reduced bacterial populations by the end of a 24-day incubation period. Amoebal numbers decreased in the presence of nematodes with a corresponding increase in nematode numbers which reached a maximum of 230 nematodes/g of soil in the treatment with amoebae and glucose additions. After 24 days the nematode populations in the treatments without carbon additions were dominated by resistant dauer larvae indicating the unavailability of food. Although larval numbers were high in the treatments with glucose additions, the adult component of the population was still increasing at the end of the 24-day experiment. The effect of the presence of amoebae on nematode abundance was of the same magnitude as addition of 600Μg glucose-C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013279
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  • 2
    Electronic Resource
    Electronic Resource
    Trophic interactions in soils as they affect energy and nutrient dynamics. IV. Flows of metabolic and biomass carbon (1977)
    Springer
    Microbial ecology 4 (1977), S. 373-380 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Flows of biomass and respiratory carbon were studied in a series of propylene-oxide sterilized soil microcosms. One-half of the microcosms received three pulsed additions of 200 ppm glucose-carbon to mimic rhizosphere carbon inputs. Biotic variables were: bacteria (Pseudomonas) alone, or amoebae (Acanthamoeba) and nematodes (Mesodiplogaster) singly, or both combined in the presence of bacteria. Over the 24-day experiment, respiration was significantly higher in the microcosms containing the bacterial grazers. Biomass accumulation by amoebae was significantly higher than that by nematodes. The nematodes respired up to 30-fold more CO2 per unit biomass than did amoebae. Similar amounts of carbon flowed into both respiratory and biomass carbon in microcosms with fauna, compared with the bacteria-alone microcosms. However, partitioning of available carbon by the microfauna varied considerably, with little biomass production and relatively more CO2-C produced in the nematode-containing microcosms. The amoebae, in contrast, allocated more carbon to tissue production (about 40% assimilation efficiency) and correspondingly less to CO2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02013280
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of the 7 march 1970 solar eclipse on atmospheric electricity, a contribution to the boundary layer discussion (1972)
    Springer
    Meteorology and atmospheric physics 21 (1972), S. 221-245 
    Details
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Description / Table of Contents: Zusammenfassung Während der Sonnenfinsternis vom 7. März 1970 wurden im östlichen Teil der USA an fünf Bodenstationen und mittels dreier Serien von aerologischen Messungen das luftelektrische Feld, der Vertikalstrom, die Raumladung und die Leitfähigkeit gemessen. Die Frage, ob die beobachteten luftelektrischen Folgen der Sonnenfinsternis durch bodennahe Vorgänge (im Zusammenhang mit dem Austausch) erzeugt werden oder auch durch Prozesse in großer Höhe, kann immer noch nicht sicher beantwortet werden. Es war jedoch möglich, eine spekulative Hypothese vorzuschlagen, mit der — auf Grund der erstgenannten Annahme —die Mehrzahl der Beobachtungen erklärbar wird. Der vielleicht wichtigste Gewinn aus dieser Beobachtungsreihe ist eine bessere Abschätzmöglichkeit für die bei solchen Messungen zu stellenden Anforderungen. Wie es außerdem scheint, können einfache Modelle die Aufeinanderfolge des beobachteten Verlaufs nicht erklären.
    Notes: Summary Measurements of the electric field, the vertical current density, space charge and conductivity have been carried out at five ground stations and three series of free-air measurements during the 7 March 1970 solar eclipse in and near the totality zone. The problem whether the observed variations in electric parameters are caused by near-ground processes (related to eddy diffusion) or by highaltitude processes is not yet solved. It was possible, however, to offer a speculative explanation with the first assumption for the majority of the observations. The most important conclusion is the ecquisition of a better understanding of the requirements for measurements made for investigating solar eclipse effects. Also, it seems that simple models are not sufficient to explain the sequence of variations seen in the data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02247974
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  • 4
    Electronic Resource
    Electronic Resource
    Errors in the gerdien measurement of atmospheric electric conductivity (1991)
    Springer
    Meteorology and atmospheric physics 46 (1991), S. 101-112 
    Details
    ISSN: 1436-5065
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Notes: Summary The measurement of conductivity has been an essential part of most atmospheric electricity research programs during the past century. This measurement is known to be vulnerable to a variety of potentially significant errors which can be separated into those resulting from diffusion of ions and those produced by electrical forces. Diffusion errors are caused by inlet tubing, screens, and inlet covers; and electrically produced errors may result from the effect of the accelerating potential or the potential of the apparatus itself. Detection and quantification of these errors has been the subject of several past studies which are discussed in detail. In this paper, a series of measurements and theoretical analyses is described in which the effects of each error mechanism are isolated, measured, and analyzed, and in which prior error reduction schemes are tested. It is shown that diffusive losses in inlet ducting and structures can be significant, and analytical estimations of these losses are presented which agree well with the measurements. The losses produced by electrical forces may also be significant even when plausible ameliorative measures are taken, and operating constraints to avoid this error source are developed. Past measurements of diffusive loss are found to be consistent with these results except in one case where improper operating conditions are indicated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01026627
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  • 5
    Electronic Resource
    Electronic Resource
    Patterns of trace metal accumulation in crayfish populations (1978)
    Springer
    Bulletin of environmental contamination and toxicology 20 (1978), S. 120-127 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01683495
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  • 6
    Electronic Resource
    Electronic Resource
    Bioconcentration patterns of zinc, copper, cadmium and lead in selected fish species from the Fox river, Illinois (1980)
    Springer
    Bulletin of environmental contamination and toxicology 24 (1980), S. 727-734 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01608180
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  • 7
    Electronic Resource
    Electronic Resource
    Habitat selection in two species of short-horned grasshoppers (1979)
    Springer
    Oecologia 38 (1979), S. 359-374 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The roles of thermal and hydric stress in habitat selection by two species of short-horned grasshoppers was investigated through field and laboratory studies and computer simulation experiments. Psoloessa delicatula was found to possess an elaborate repertoire of thermoregulatory postures and shade seeking behavior. This grasshopper was found in habitats in the shortgrass prairie in which bare patches of ground were common. It was found to regulate its body temperature to a relatively constant level over the course of a sunny day. Eritettix simplex was found in patches of dense vegetation, and its body temperature was usually similar to ambient temperature. During controlled laboratory experiments, E. simplex nymphs lost water rapidly and thus were presumed to be restricted to more mesic environments where desiccation stress is less. A thermal energy budget model was constructed and showed that the habitat selected by P. delicatula would allow behavioral thermoregulation whereas the habitat selected by E. simplex should preclude regulation of body temperature by behavioral means.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00345194
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  • 8
    Electronic Resource
    Electronic Resource
    Mineralization of cellulose in the presence of chitin and assemblages of microflora and fauna in soil (1983)
    Springer
    Oecologia 60 (1983), S. 103-110 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nitrogen content is an important factor controlling decomposition of resistant substrates. We examined the decomposition of purified cellulose in the presence of a structurally similar, resistant organic N compound, chitin. Carbon-14-labelled cellulose was added to sterile ari-dried sandy loam soil in flasks, half of which were also amended with purified chitin. Grassland soil organisms-a fungus (Fusarium oxysporum) or a bacterium (Flavobacterium sp.) with or without their respective nematode grazers (Aphelenchus avenae or Pelodera sp.) were added to the substrateamended soils, and decomposition was monitored by carbon dioxide evolution and NH 4 + −N mineralization. More 14CO2 was evolved and at a higher rate from the fungal treatment than from the bacterial treatment. Grazing enhanced 14CO2 and total CO2 evolution and NH 4 + −N mineralization in the bacterial treatments and NH 4 + −N mineralization in the fungal treatments. Nitrogen was mineralized both from native organic sources and from chitin. The addition of chitin did not enhance and, in most cases, decreased cellulose decomposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379327
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  • 9
    Electronic Resource
    Electronic Resource
    Pollution-Tolerant Allele in Fingernail Clams (Musculium transversum) (1998)
    Springer
    Archives of environmental contamination and toxicology 35 (1998), S. 302-308 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract. For nearly 50 years, the fingernail clam (Musculium transversum) was believed to be virtually eliminated from the Illinois River. In 1991, workers began finding substantial populations of M. transversum in the Illinois River including several beds in and around the highly polluted Chicago Sanitary District. In order to determine if populations of M. transversum from polluted sites exhibited any genetic response to the high levels of toxins and to examine the genetic structure of several populations of M. transversum for any changes due to the population crash, starch-gel electrophoresis was performed on M. transversum from three Illinois River localities and four Mississippi River basin locations. The sampled populations produced an inbreeding coefficient (FIS) of 0.929, indicating that the populations were highly inbred. The results of a suspected founder effect due to a bottleneck was suggested by an FST= 0.442. The isozyme Glucose-6-phosphate isomerase-2 (Gpi-2) produced allelic frequency patterns that were consistent with expected patterns of a pollution-tolerant allele. Polluted sites exhibited elevated frequencies of Gpi-2 100 whereas nonpolluted sites exhibited elevated frequencies of Gpi-2 74 . This frequency pattern suggested that natural selection was occurring in populations under severe toxic pressures, leading to an increase in the frequency of the allele Gpi-2 100 . Therefore, Gpi-2 100 is a possible pollution-tolerant mutation in M. transversum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002449900380
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